Mobile Mapping – Highways
Mobile Mapping Technology allows the collection of 3D geospatial data from a moving vehicle platform. Satellite Positioning is supported with an Inertial Measurement Unit generating a smoothed Vehicle Trajectory, to which a 3D laser Scan Point Cloud and Calibrated Imagery are referenced.
Whilst allowing greatly improved productivity and data resolution, detailed mission planning and analysis are needed to extract maximum benefit from the technology.
Working in partnership with a local Geospatial company The Severn Partnership carried out mobile mapping along 8km of a busy main road in Cornwall. The client required a fast turnaround of data that prohibited the booking of traffic management and road closures.
Severn Partnerships service uses a unique instrument which can be mounted onto any vehicle and survey roads, motorways, rail, and water ways.
The project aim was to rectify localised drainage issues along this undulating stretch of highway. Deliverables required a 3D Laser Scan Point Cloud to be merged with existing Aerial Lidar Data on OSGB36 Grid, along with a standard 3D CAD Vector model of the site.
The road is typical of many UK ‘A Roads’ with little or no hard shoulder for safe daytime access or parking, and vehicle speeds of 60mph or more.
These hazards meant a traditional survey approach would require Active Traffic Management for Surveyors to complete their observations, meaning an 8 week lead in time to site works. Traditional Survey techniques would require 2 weeks on site and a further 2 weeks for office processing.
With a total programme of 12 weeks not acceptable, an alternative solution was required.
Through the use of Mobile Mapping Severn Partnership were able to complete Laser Scanning of the highway in a few hours during normal daytime working hours without disrupting traffic, and Surveyors were removed from the open highway completely.
Image with point cloud data overlayed captured with Severn partnerships mobile mapping service.
- 3D CAD Vector Drawing
- Local GNSS Static Base Station
- Ground Control Points only where safe to access off the open carriageway
- Multiple Passes with the Pegasus:Two to ensure data repeatability and omit shadows
- Post Processing to OSGB36 Grid
- Mobile Lidar matched to existing Aerial Lidar dataset
- Georeferenced Site Imagery supplied to client to aid digitising, using free ArcGIS viewer plugin
Why use Severn Partnership? Well this info-graphics explains why !